how does water get to the hot water heater when you drain it

larry barnhart wrote:

Old-Biscuit wrote:

2oldman wrote:

enblethen wrote:
The water heater needs an air space near the top. Water should not be over the pressure relief valve port.

How do you control that?

Normal filling of water heater will establish the air pocket by design of tank and position of dip tubes.
See previous picture.......

Over time the air pocket can be absorbed into water........then you will need to re-establish the air pocket or pressure will increase due to expansion of water when heated (typically PRV will weep when this occurs).

To re-establish air pocket
Turn off water supply
Open hot side of faucet to relieve line pressure
Hold open PRV via lever until water stops running out
Let PRV snap close
Turn on water supply
Close faucet

I turn off the faucet and then go out and turn on the water supply. I think this is your way but said it wrong.
chevman

Nope...didn't say it wrong

enblethen wrote:
You do not want the water heater tank "full".
Turn on pump and a faucet to fill tank.

Actually, for the bleach water pass he does.. Let it fill with the TPR valve open so it's as full as possible,, Then drain it, Then flush the system then flush again this time adding baking soda, then flush again with fresh water.

Then drain the water heater CLOSE the TPR valve, and let the pump refill it properly.

Old-Biscuit wrote:

2oldman wrote:

enblethen wrote:
The water heater needs an air space near the top. Water should not be over the pressure relief valve port.

How do you control that?

Normal filling of water heater will establish the air pocket by design of tank and position of dip tubes.
See previous picture.......

Over time the air pocket can be absorbed into water........then you will need to re-establish the air pocket or pressure will increase due to expansion of water when heated (typically PRV will weep when this occurs).

To re-establish air pocket
Turn off water supply
Open hot side of faucet to relieve line pressure
Hold open PRV via lever until water stops running out
Let PRV snap close
Turn on water supply
Close faucet

I turn off the faucet and then go out and turn on the water supply. I think this is your way but said it wrong.
chevman

Old-Biscuit - I see you are using this infamous drawing showing how the water systems work in the RVs. I use the same drawing alot on this end as well..

I just checked with the owner of this drawing at his home site which states this is OK for any us to use haha... I think it is a great drawing...

Mark Nemeth's home page states "All material on this website is © 1997-2012 Mark S. Nemeth
You are free to reproduce or copy any part of this website and/or it's contents for your own personal (non-commercial) use only. Any other use of any material contained herein requires permission from the author. "

Actually he has improved on his drawing by adding a few more items to it..



His home page shows alot of technical info that alot of us keep referring too.

RV TECH INFO ARTICLES

Roy Ken

I assume if you attach the hose to the water inlet without filling it with water, turn the water on, then open a hot water valve, the air in the hose should go into the water heater, the excess coming out and the air pocket being at max? Right?

I have had to do it several times in my 11 years of full timing - when the PRV starts weeping.

Old-Biscuit wrote:
Basic RV water system

This is perfect, thanks!

Once in a while I notice the HW will spit at me when I first turn it on. I guess that's why. Thanks.

2oldman wrote:
Ok. Does anyone actually DO this?

Weekend/vacationing campers/trailers usually don't have to as the water heater is filled/used/drained routinely

Long term users will need to when they find the PRV weeping.

When we travel weekly don't find it to be an issue.
Have found PRV weeping when we stay put longer

Ok. Does anyone actually DO this?